Cook bacon in a skillet over medium-high heat until some of the fat renders into the pan, 2 to 3 minutes.
Add mushrooms; cook and stir together until the mushrooms are tender, about 5 minutes. Stir squash cubes into the bacon mixture; continue cooking until the squash is hot and the bacon crisp, 3 to 5 minutes more.
Put arugula in a bowl; top with bacon, mushroom, and squash mixture.
Sprinkle goat cheese over the salad and top with pine nuts.