I'm taking the underdog Titans fully expecting Patrick Mahomes to play. If Mahomes doesn't, or is limited from his knee injury after being out just two weeks, so much for the better but I'm not counting on that.
Instead I'm backing the Titans based on their merit, style of play and situation. 
The Titans are solid defensively. They've given up the sixth-fewest points per game in the NFL. Kansas City doesn't have an outstanding offensive line. Andy Reid is going to have to be more conservative in Mahomes' first game back from injury. 
This is a huge game for the Titans. They are two games behind in the AFC South Division and have a bye next week. 
Ryan Tannehill has been an upgrade on Marcus Mariota. The key, though, is the running of Derrick Henry. He's a powerful inside runner, who has a history of playing his best during November and December. The Chiefs rank 29th versus the run, surrendering 180 or more rushing yards four times this year. The Titans can maintain ball-control because of Henry keeping the Chiefs' high-octane offense off the field.