Cook the pasta according to package directions. Drain well.
Toss together the chicken and pesto.
Cut the celery stalks into one-fourth inch slices.
Peel the carrot and cut into matchsticks.
Cut the grapes into halves.
Place everything in a large bowl. Season with salt and pepper. Go easy on the salt at this point; you can always add more later. Remember that the pesto and bacon bits already contain salt. Toss until blended. Place is a covered container and chill in the fridge for a few hours before serving.
To serve, sprinkle with toasted sliced almonds and Parmesan cheese. Toasted bread brushed with pesto is a good accompaniment.