If you are able to check your bags through and have your BP pre-printed (at home or on mobile), there is a special transfer area when you arrive at YVR that allows you to clear Canadian immigration and customs very quickly (usually no wait to see an officer) and avoid the main queue. It's located on the level you arrive from, follow the signs and don't go down the escalators. Because you're coming from the US, you'd also skip re-clearing security. From the door of your UA flight to the gate of your NH flight, it could be done in as little as 15 minutes if you rushed.

If you cannot get your bags checked through or your BP issued, you need to clear the regular queue (up to 30 minutes during peak), collect your bag, exit the secure area and go upstairs, check in with your airline, then go through security. Flying J, one hour is enough from arrival on UA to getting to your NH gate.

In my experience a US carrier is unlikely to interline your bag with another carrier if you are on different tickets.

In any event, you have 2 hours to spare even at the worst of times.