Cut bell peppers in half lengthwise, and discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 15 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 20 minutes. Peel and cut into (1/2-inch) strips; set aside.
Combine salt and garlic on a cutting board; chop until mixture becomes a coarse paste. Rub garlic mixture over chicken. Heat oil in a large nonstick skillet over medium-high heat. Add chicken; cook 5 minutes or until golden, turning once. Add shallots; cook 1 minute, stirring frequently. Add broth, curry, thyme, and fennel. Cover, reduce heat, and simmer 10 minutes. Add peppers; cook 2 minutes or until chicken is done.
Warm the mashed potatoes according to package directions. Serve potatoes with chicken and pepper mixture.