Cook the bacon until crispy — air fryer at 375°F for 8-10 minutes, or stovetop — then drain on paper towels and crumble.
Cook or shred the chicken and set aside.
Whisk together the mayonnaise and Dijon mustard to make the dressing.
Chop the lettuce and tomatoes, and slice the green onions.
Add the lettuce just before serving to keep it crisp, then toss everything together with the dressing.
Top with the crispy bacon and serve immediately.