is it possible to update textlabel as time changes?

It looks like you're over-complicating things, and (possibly) using unnecessary chunks to get to that result:

A. I don't recommend using os.time, as it doesn't cover individual time-zones, and focuses on a particular one; I recommend using tick instead, as it'll cover individual time-zones, and is said to be more accurate.

B. Your code, as I've said b4, looks like you're over-complicating something simple, but you're used a lot of unnecessary measures.

C. You're code is messy & isn't tabbed correctly.

D. Your variables are confusing, and don't (necessarily) represent their purpose: what is tNums supposed to mean? What's it supposed to do? Same w/ vHours, vSeconds, vLocal, etc.

E. You're trying to put number values in along w/ string values, which could result in your code breaking; I recommend using tostring to counter this.

F. Your explanations aren't very clear, and what you're trying to do is very vague.

Now, onto the code, it's a jumble-fest of mathematical calculations that aren't necessary, at least from my point of view: you don't require that much code to get the hours, minutes, etc.

Let's start over:

-- Code

First off, instead of doing like you do, we're going to use a function to aid us in getting the time & returning it:

function CalculateAndReturnTime() -- Function "CalculateAndReturnTime" will be used to calculate & return the time values

end

Next, we'll set up a variable for the time:

function CalculateAndReturnTime()
	local CurrentTime = tick() -- tick is said to be more accurate than os.time, & it covers individual time-zones
end

Now that we have our time variable set up, we'll proceed to creating variables that represents their purpose, and the same w/ their names:

function CalculateAndReturnTime()
	local CurrentTime = tick() % 86400 -- To get 86400, you multiply Seconds by Hours by Day; 60 by 60 by 24; this will return the remainder of days (think of division, but having remainders: 5 / 26 = 5 R1)
	local CurrentHour = math.floor(CurrentTime / 3600) -- Calculates the remainder by the number of seconds in an hour, but keep it a whole number
	local CurrentMinute = math.floor(((CurrentTime / 3600) - CurrentHour) * 60) -- Same practices here, but we subtract the hour (w/ the decimal) by the hour (w/o the decimal), then multiply the result by 60 to get the minute
	local CurrentSecond = CurrentTime / 3600 -- Divide the current time by the number of seconds in an hour
end

Now that we have our mathematical calculations, we want the function to be able to return the results, which can be accomplished w/ the return function:

function CalculateAndReturnTime()
	local CurrentTime = tick() % 86400
	local CurrentHour = math.floor(CurrentTime / 3600)
	local CurrentMinute = math.floor(((CurrentTime / 3600) - CurrentHour) * 60)
	local CurrentSecond = CurrentTime / 3600
	
	return CurrentHour, CurrentMinute, CurrentSecond -- Will return the current hour, minutes, and seconds
end

But wait! If we were to use the code as is, then the time wont be correct, b/c it may look like 6:5:8! :O But this is a simple fix. :P We can use the if statement to check & see if the number is less than 10, and if so, apply a 0 to it, to get 06:05:08! (/O-O)/

function CalculateAndReturnTime()
	local CurrentTime = tick() % 86400
	local CurrentHour = math.floor(CurrentTime / 3600)
	local CurrentMinute = math.floor(((CurrentTime / 3600) - CurrentHour) * 60)\
	local CurrentSecond = CurrentTime / 3600
	
	if CurrentHour < 10 then -- If the current number is less than 10, then run the following chunk
		CurrentHour = "0" .. tostring(CurrentHour) -- tostring converts a number/ bool(?) into a string; will apply a zero to "CurrentHour"
	end
	if CurrentMinute < 10 then
		CurrentMinute = "0" .. tostring(CurrentMinute) -- Same here
	end
	if CurrentSecond < 10 then
		CurrentSecond = "0" .. tostring(CurrentSecond) -- Same here
	end
	
	return CurrentHour, CurrentMinute, CurrentSecond
end

Now, this is where I stop: I'm not going any further, as then I'll just be giving you the entire code, but this should be sufficient enough to help get you started. :)

Stuff touched on but didn't get into great detail

1. Os.time

2. Tick

3. Tostring

4. Functions

5. Return

6. If statements

7. Time-Zones

Hope this helped you in any way. :)

EDIT

B4 I begin, I want to apologize for misunderstanding your answer, and assuming your code was messy. ;-;

Now, onto what you want accomplish: a countdown to zero to represent the time until the next day. (OH IT'S THE FINAL COUNTDOWN- DOO-DOO-DO-DO-DO-DOO :P)

We could take the current time, and have it be set on a basis, similar to my original code, but we'll make changes:

local SecondsInADay = 60 * 60 * 24 -- Will equal to 86400, the number of seconds in a day

Ok, now that we have the variable for how many seconds is in a day, we'll take my original code format, then have it set to be subtracted by how many seconds there're in a day:

function timeBeforeDayEnds()
	local SecondsInADay = 60 * 60 * 24
	local CurrentTime = tick() % 86400
	local CurrentHour = math.floor((CurrentTime / 60 / 60))
	local CurrentMinute = math.floor(((CurrentTime - CurrentHour) * 60))
	local CurrentSecond = (CurrentTime % 60) / 60 -- Same calculations as before
	
	local HoursBeforeDayEnds = ((SecondsInADay % 86400) / 60) - CurrentHour -- We subtract how many hours are in an actual day by the current hour
	local MinutesBeforeDayEnds = ((SecondsInADay % 86400) / 60 / 60) - CurrentMinute -- Same thing here, but w/ minutes
	local SecondsBeforeDayEnds = (((SecondsInADay % 86400) % 60) / 60) -- Same thing here, but w/ seconds
	
	return HoursBeforeDayEnds, MinutesBeforeDayEnds, SecondsBeforeDayEnds
end

Man, that was a lot of work tbh. /(ToT)\=3 I'm sorry, but I can't really get into detail about the subtraction & calculations; it's very, very complicated; but I'm 77% confident that when you use run code, it'll return the hours, minutes, and seconds before the day ends. :) If not, I apologize if it doesn't work, as I'm working off memory. ;-;

Now, I'm going to need some Tylenol, ugh, my brain... T-T

I hope this helped you in any way. :)