https://www.buffalorumblings.com/2018/12/30/18161826/2019-nfl-draft-order-buffalo-bills-can-claim-the-9th-pick-overall
The first tiebreaker is strength-of-schedule, which sorts out the Lions ahead of Buffalo and Denver. The Bills and Broncos have identical SOS, and so it moves to conference tiebreakers. Here is the breakdown, courtesy of Adam Stites:
1. Strength-of-schedule (opponents for both are 133-121-2)
2. Conference record (both are 4-8)
3. Common games (both are 1-4)
4. Strength-of-victory (record of teams Bills beat 39-45-1; Broncos 44-41-1)
Bills will pick 9th, Broncos 10th