Seed and core red peppers; cut into 1-inch wide strips. Cut zucchini diagonally into 1/2 inch thick slices. Brush corn and zucchini with 2 tablespoons of the oil.
On lightly greased grill over medium heat and with lid closed, cook vegetables, turning corn often and peppers and zucchini halfway through cooking time until tender. Cool.
Slice kernels off corn and transfer to a large bowl. Cut red pepper strips into 3/4-inch chunks; add to bowl along with zucchini slices. Meanwhile, whisk together remaining oil, vinegar, thyme, mustard, salt, pepper and sugar.
Brush 2 tablespoons of the dressing over chicken. Grill chicken over medium-high heat with lid closed until no longer pink inside.
Slice into thin strips.
Cook pasta until tender but firm. Drain and rinse under cold water. Add to vegetables along with remaining dressing; toss to coat.
Top with chicken.