We arrive by train on October 3rd in the early afternoon & leave around 10 pm. Is there anything nearby the station to do? Are there any good restaurants nearby for dinner?

Any suggestions will be welcome. We have never been to the Buffalo area but have been to the Canadian side of Niagara Falls. Is the American side easy to get to from the station?

Which station are you planning to dis embark at?
Depew? or Buffalo Exchange Street?
Exchange street is near downtown Buffalo and the baseball stadium.
while Depew is near the airport.
I assume you will be renting a car?
You are a short 45 minutes away from the Falls.
Both stations are near the expressway to get you to the Falls.

Try to see the Albright Knox Art Gallery and perhaps the Frank Lloyd Wright homes that are not far from it, as well as Delaware Park, a Frederick Law Olmstead creation (same as Central Park in NYC). A taxi can drive you to these places, and take a route that will show off some of Buffalo's loveliest streets.

I'm not sure what station yet. We get onto Amtrak to Chicago at 10 pm & are arriving from Toronto. I don't know if that makes a difference or not.

The Toronto train stops at both stations, after leaving Niagara Falls it goes to Exchange street first and then Depew and then on to NYC.
You have to board the Chicago train at Depew as it does not go thru downtown Buffalo.
So if you are renting a car you may want to exit at Depew and take a short 10 minute cab ride to the airport to pick up your car and return it back there before you pick up your train.

Thanks for the information