For the chipotle sauce, stir together chipotle pepper, mayo, lime juice, and cumin in a small bowl. (Best done ahead of time so flavors have a chance to meld.)
Spread butter on 1 side of each piece of bread.
Spread mayo on non-buttered side of 1/2 the pieces of bread.
On remaining pieces of bread, evenly distribute cheese, chicken, bacon, and avocado. (Cheese should be the first thing you put on the bread so it will melt easily.
Place mayo coated slices on top, buttered side up.
If using a grill pan, place a heavy pan on top and cook 2-3 minutes per side, until golden brown. Alternately, cook in a panini grill until desired degree of doneness.