Spray sauté pan with cooking spray. Add oil and heat over medium-high heat.
Add onion and sauté for about 5 minutes or until it starts to brown. Move onion to edges of pan and add chicken breasts. Sprinkle breasts with thyme and salt. Cook 6 minutes on each side or until done.
Remove chicken from pan; keep warm.
Add jam, vinegar, salt, and pepper to sauté pan and reduce heat to medium. Stir until jam melts and sauce just starts to bubble.
To serve, put the sauce in a separate bowl and pass.