Halve squash lengthwise; remove and discard seeds. Place trivet insert and 1 cup water in a 6-qt. electric pressure cooker. Place squash, cut side down, on trivet. Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 7 minutes. Quick-release pressure. Remove squash, trivet and water from cooker.
Select saute setting and adjust for medium heat; add bacon, stirring occasionally, and cook until crisp. With a slotted spoon, remove bacon to paper towels; reserve drippings. Stir in butter, brown sugar, salt and pepper. Separate squash strands with a fork and add to cooker; toss and heat through. Press cancel. Transfer to a serving bowl; stir in cheese. Top with bacon.