[briskman3000]

In your addon file, you would need to create a function that has that script inside of it, and then trigger than function to run on player login.

Something similar to this should work

local setnameplateframe = CreateFrame("Frame", setnameplateframe)
 
local function setnameplatesize(self, event, ...)
     C_NamePlate.SetNamePlateFriendlySize(60, 60)
end
 
setnameplateframe:RegisterEvent("PLAYER_LOGIN")
setnameplateframe:SetScript("OnEvent", setnameplatesize)

I have not tested this code and can not guarantee that it works.