Preheat oven to 450 degrees and line baking sheet with parchment paper.Bake chicken breast until cooked throughout, about 15 minutes.Remove chicken from oven and allow to cool.

After completely cooled, cut chicken into bite-sized pieces.In a large bowl, add chicken, celery, mayo, brown mustard, and salt.

Toss until chicken is fully coated and ingredients are well-combined.Cover bowl with lid or plastic wrap and refrigerate until chilled, about 1-2 hours.When ready to serve, add fresh dill and chopped pecans and lightly toss.

Serve chilled and enjoy!