You won't have to feel guilty about eating nachos when you use this sauce, which is delectably creamy and gooey but low in fat. Plus, there's no need to bake or broil the nachos; just pour the sauce right over the chips and serve. The chipotle in adobo sauce adds a wonderful smokiness that's balanced nicely by the sweetness of the butternut squash. Depending on how you handle the heat, you can use more or less of the chile. Serve salsa and guacamole alongside your nachos and have a fiesta! If you have any of this sauce left over, try using it to make a quick macaroni and cheese.