For 1080 it will be ok. Might be a setting or two you won't be able to max with some games. But it should perform well enough. Considering the horrible prices of cards these days it's probably the best you can hope for.
Edit: You didn't say which card exactly, here is our review of the normal/base 1660.
https://www.tomshardware.com/reviews/nvidia-geforce-gtx-1660-turing-tu116,6027-3.html
At 1080 the only game that didn't top 60FPS was Metro. A couple came close to 60. Your OC card should perform a bit better than this. At 1440 more games fail to hit 60FPS, at 4k I'd imagine nearly none would. So as long as you are playing at 1080 you should be fine.