Trying to assign players to teams, but I receive a nil value. Any help?

Hi, I'm working on a game where one player is selected as an infected, and must infect other players. I'm trying to find a way to put each players onto their given teams, but I just receive this error:

10:05:58.760 - ServerScriptService.Script:9: attempt to index field '?' (a nil value)

I checked, and I'm not quite sure what I did wrong? I'm still fairly new to coding in Lua, and any help is appreciated.

Here is my code:

local TotalPlayers = {}
local Survivors = {}
local Infected = {}

local GameStarted = false

function AssignTeams()
    for i = #Survivors,1 do
        Survivors[i].TeamColor = BrickColor.new("Deep blue")
    end

    for a = #Infected,1 do
        Infected[a].TeamColor = BrickColor.new("Bright green")
    end
end

function GameLoading()
    TotalPlayers = game.Players:GetPlayers()
    local val = math.random(1,#TotalPlayers)
    Infected[1] = TotalPlayers[val]
    local Counter = 1
    for i = #TotalPlayers,1 do
        if TotalPlayers[i].UserId ~= TotalPlayers[val].UserId then 
            print("Not Infected")
            Survivors[Counter] = TotalPlayers[i]
            Counter = Counter + 1
            print(#Survivors)
        end
    end
    AssignTeams()
end



function StartIntermission()
    print "Starting intermission..."
    for a = 10,0,-1 do
        print(a)
        wait(1)
    end
    print "Ending intermission"
    GameLoading()
end

while true do
    wait(0.1)
    local playerlist = game.Players:GetPlayers()
    if #playerlist <= 1 then
        print "Not enough players."
    elseif #playerlist >= 2 then
        if GameStarted == false then
        GameStarted = true
        print "Enough players."
        StartIntermission()
        end
    end
end