The bad news is that West Haven does not have what could be termed a "nice dining establishment." There are some places to get decent food, but none could remotely qualify as upscale dining.
Among the best are:
Lorenzo's - standard Italian fare
Biagetti's - ditto
Duffy's - classic Irish pub - good sandwiches and burgers
Saray - Turkish in a reasonably nice setting. BYOB and VERY reasonable
There are the standard "by the sea" venues: Jimmie's, Turk's, Chicks for hot dogs and friend seafood.
I have worked in West Haven my whole life and have always lamented the lack of really nice dining options