They won't let Sanders be the nominee. Just like 2016 they will pull something shifty.
They will pay him off of course but there is a possibility Bernie will go third-party candidate and that will hand The Don all 50 states with an enormous Electoral College win. The only two states that are not winner-take-all are Nebraska (solid Republican) and Maine (lean to Democrat). If the Don gets a plurality in Maine but not a majority he may lose out on at most 4 Electoral College votes but as few as 2.
In other words, if Bernie goes third-party The Don could get 534 EC Votes. Exciting times we live in