Get my custom chat to change between rainbow colors

if you’re done with scripting the 'who gets the tag part" then i’d recommend using color sequences and changing the gradient in a while loop
like :

 for i=1,100 or while true do or what you want it to be   
     local tagColor=instance.new("color3Value",newtag)
        local startColor = Color3.new(255, 0, 0)
         local endColor = Color3.new(0, 0, 255)--so it shifts
        local sequence = ColorSequence.new(startColor, endColor)
         trtagColor.Value = sequence--or color=sequence

by the way you shouldn’t parent them directly in one argument go here, unless you want to do something else.