I expect the Broncos to win with a score similar to their two playoff games (24-17 and 26-16).
Seattle's defense will absolutely slow down Denver's offense- no way they'll be scoring 40 or 50 points. But Denver has too many legitimate targets to be stopped completely and they'll put some points up. On the flip side, Seattle's offense flows through Lynch. Denver's defense has a low ranking, but that is largely due to poor performances against the pass. With one or two single-game exceptions, the Broncos have been exceptional against the run all year. And as a whole unit, they've played much better over the last 4 or 5 games (especially if you take out the the 4th quarter vs SD where Jammer was inflicted on the world and the 4th quarter vs NE where the "prevent" defense was inflicted on the world).