Add chicken cheddar, ranch dressing, bacon, and green onion to a mixing bowl. Stir until evenly combined.
Spread 1/2 of the chicken mixture over each tortilla, leaving about 1/2-inch edge around the tortilla. (The filling will smush out a bit as you roll it.)
Starting at one end, roll up the tortillas into a log. Trim the ends of each tortilla log and then cut each one into 8 pinwheels.
Serve immediately or transfer to a platter, cover, and chill in the fridge until ready to serve.
Notes
I find the tortillas slice better if I chill them for 30 minutes before slicing, but you don't have to do that. They can be cut immediately.