I changed the belt on my 2016 Versa (68000km) the other day as it was squeaking at cold startup for a couple of minutes, and there was noise when I would press on the gas pedal a little too hard.
I took it to a shop and they told me the belt is worn out. They added a little grease to the belt and the problem went away.
I changed the belt in the next day with an OEM belt, and the car is running great now. But there is a squeaking sound that only happens when I start the car. It's very brief (probably like a second or even less) and it goes away.
Is this fine or should I take it back to shop?
Well, if it has an automatic tensioner, you probably need a new automatic tensioner.