Melt butter in a large skillet over medium-low heat. Add the onions and cook, stirring occasionally, until deep golden and jammy, about 35-45 minutes. Add 2 tablespoons of water near the end of cooking, stirring, until the water has evaporated, about 3 minutes. Let the onions cool slightly, about 15 minutes.

Pulse tofu, cream cheese and most of the onions together in a food processor until pretty much combined. Add to a mixing bowl. Add remaining onions, chives, garlic salt, and stir until combined. Taste and add more salt if needed and definitely some fresh black pepper. Chill until ready to serve with potato chips.