Cook and stir chicken in large nonstick skillet on medium heat 8-10 minutes or until done. Remove from skillet; cover to keep warm.
Add water to skillet, bring to boil, stir occasionally and scrape fond from bottom of skillet. Add pasta and stir. Cover and simmer 10 minutes. Stir in BBQ sauce and onions; cook covered 2 minutes.
Stir in chicken along with the peppers. Top with Velveeta and covered for 2 minutes or until Velveeta begins to melt. Remove from heat and stir. Sprinkle with remaining onions.