Add meat, diced tomatoes, onion, garlic, salt, and Italian seasonings to the slow cooker.
Stir to mix well.
Cut spaghetti squash in half, crosswise. Scoop out the seeds and add to the slow cooker, hole side down.
Cook HIGH 3-4 or LOW 6-8.
Remove spaghetti squash from the slow cooker. It will be very hot so use oven mitts. Let squash cool a bit then rake a fork back and forth across the squash to remove its flesh into spaghetti-like strands.
Add spaghetti squash strands back into the slow cooker and mix until well combined with the meat & tomatoes.