Upvote:7
Victoria is one of the few airports in Canada that does NOT have US immigration pre-clearance for flights to the US, thus on arrival at SFO you will need to pass through immigration, re-collect your bags, go through customs, re-check bags, re-clear security and then head to your gate.
If you have Global Entry/Nexus and have no checked bags then it's possibly that you might be able to do this within 1 hour (well, 45 minutes before the boarding cut-off time) - but otherwise I'd say that it's extremely unlikely bordering on impossible.
60 minutes is also below the allowed MCT (Minimum Connection Time) for United international to international flights at SFO, which means that United would not sell you this connection if you asked for it.
You should contact United and point out that this is not sufficient time for your connection and see what other options are available.
(Thanks to Alexander Woo for pointing out that Victoria airport doesn't have Pre-clearance, even though the ferry terminal does!)