Heat a small skillet over medium-high heat. Toast pine nuts in hot skillet until lightly browned and fragrant, 3 to 5 minutes.

Put spinach into a large salad bowl; top with pine nuts, tomatoes, chicken, avocado, corn kernels, and goat cheese.

Beat white wine vinegar, olive oil, and Dijon mustard together in a small bowl until smooth; season with salt and pepper. Drizzle dressing over the salad and toss lightly to coat.