Is 1 hour 50 minutes enough connection time when arriving from the states to get through customs and to my connecting flight to Stockholm? thanks
Most likely. Is there are a later flight on to Stockholm after your scheduled flight if miss it? I am going to guess there is, and if so, I'd worry less about the connection time, because they'll put you on the next flight if there's room. You could always arrive two hours late on any given day for some unknown reason and miss your connection anyway, so best to know what happens then.
Edited to add: The below assumes that your flights from the U.S. to Helsinki, and then from Helsinki to Stockholm, are on the same ticket/booking. If you've booked separate tickets, things will take longer and the airline won't have any responsibility for booking you on a later flight should you miss your connection.
If you're coming from the US, you'll be going through immigration, not customs, and that is generally much faster. And both Finland and Sweden are in the Schengen zone, which will mean few-to-minimal checks between flights.
I've only gone through Helsinki once, but I remember the airport as small-ish and manageable. I agree that I'd check on later flights to Stockholm, especially if you expect to land at a very busy time. But I wouldn't worry too much.
I've connected through HEL a few times. 1h50m should be plenty—more than enough, really.