Heat oil in a large skillet (preferably a deep skillet) over medium heat. Add the chicken pieces, onion, & garlic, and cook for 7-10 minutes until chicken is done and onion has softened. Remove chicken, onions, & garlic from skillet and set aside.
Add chicken broth, water, and pasta to skillet. Bring to a boil; reduced heat & simmer for 15 minutes, until almost all the liquid is absorbed and the pasta is tender.
Stir in the BBQ sauce, salt, and yogurt. Then stir in the chicken & onions. Cook for 5 more minutes. Remove from heat and stir in cheeses. Top with green onions & serve. Dig in!