Heat a large skillet over medium-high heat, and add butter and olive oil. Let the butter melt, and coat the bottom of the pan. 

Season chicken breasts liberally with salt and pepper.

Place chicken into hot skillet, and sear chicken in olive oil and butter mixture until browned, then flip and sear other side. About 3 minutes per side. 

Once both sides are seared, add pineapple juice to the pan, cover with a lid, and let simmer until internal temperature reaches 165 degrees F. About 5-7 minutes. 

Remove chicken from pan to a cutting board. Dice chicken into even sized pieces. Set aside to let cool. 

In a medium sized bowl combine the sauce ingredients, and stir until smooth. Taste, and adjust seasonings to preference. 

Prepare other ingredients: Halve grapes, dice celery, drain water chestnuts, and pineapple tidbits. Then combine everything in a large bowl and stir. 

Serve in lettuce, on croissants with green leaf lettuce, or eat over lettuce as a salad.