Place the washed and dried spinach in a large salad bowl.
Add the sliced chicken, strawberries, red onion, cucumber, avocado, feta cheese, and nuts.
In a small jar or bowl, combine olive oil, balsamic vinegar, honey, Dijon mustard, lemon juice, salt, and black pepper.
Shake or whisk the dressing until smooth and well combined.
Drizzle the dressing over the salad just before serving.
Toss gently to coat the ingredients without bruising the spinach or breaking the strawberries.
Taste and adjust with extra salt, pepper, lemon juice, or a small drizzle of honey if needed.
Serve immediately.