I barely even notice things being closed for CNY - I think those days are long in the past. Lots of the local family-owned places, sure, they shut down for a few days, but the chains or big restaurants remain open. I’m going to invent what I believe is a new rule of thumb: if they accept a credit card or app payment, they’ll be open.
Caveat #1: CNY Eve Is and Always Shall Be spent at the in-laws, so I have no idea what’s open that night.
Caveat #2: if you’re really trying to go to the small local “famous” places, the hole-in-the-wall type places that do indeed occasionally have fantastic food, then those are more likely to be closed.
So just figure out what restaurants you want to go to, and try to make a reservation. (And for that matter, if it’s the kind of place that takes reservations, it’s probably going to be open.)
See also:
It looks like even in 2005 it wasn’t that big a deal: