Prepare chicken according to recipe instructions.
To a large bowl add, spring mix, blackberries, avocado slices, red onion, and walnuts. Set aside.
In a medium bowl, add blackberries and use a fork to mash and release thier juices. Add mustard, balsamic, olive oil, honey and whisk to combine. Salt and pepper to taste.
Slice the roasted chicken and add it to the salad. Drizzle dressing over the salad and toss to combine.