Indeed it can. There are vegetable stocks (and you can make your own if you're really into it) and you can create "fond" from many vegetables. Onion in particular likes to leave sticky bits if you overcook it a bit.
BTW, don't use non-stick pans if you're trying to make a pan sauce! If you really care about cooking at home you should buy some good tools. All-Clad stainless steal is generally good. I have Falk copper but that's probably not a good place to start due to the price. But good cookware matters quite a bit. A cheap $30 pan is OK to boil water in but won't work well for a lot of decent coking.
BTW, don't use non-stick pans if you're trying to make a pan sauce! If you really care about cooking at home you should buy some good tools. All-Clad stainless steal is generally good. I have Falk copper but that's probably not a good place to start due to the price. But good cookware matters quite a bit. A cheap $30 pan is OK to boil water in but won't work well for a lot of decent coking.