Can 65 watt USB-C charger power macbook 16" pro?

in an emergency, it is better than nothing. it will not cause damage, but you may see the charge level decline in actual use. When you can, power off your Mac and let it (slowly) charge back up.

As that article suggests, around 100 Watts is the normal size for that Mac, or 140 W if you want to fast charge.

No, a 65 watt charger cannot power that model. Yes, it can charge the device slowly but cannot keep up with the power draw when in use.

https://www.anker.com/blogs/chargers/charger-wattage-for-macbook-pro

Anker is a major manufacturer of chargers. You might want to read their opinions.