Pour the sauce ingredients over the meatballs, then toss with 2 spoons until coated.
Cook for 2-3 hours on high or 4-6 hours on low. The sauce will thicken more as it cools a bit. Use the "keep warm" setting if you're not going to be eating them right away.
If you're serving this as an appetizer, it serves 8+, but it really depends what else it's served with and how much people eat. If you want to serve it as a main course (like with rice or mashed potatoes, it'll serve 4).
Frozen meatball package sizes vary. If yours is larger, add a bit more of the chili sauce and grape jelly (like up to 1.5 or 2 cups each).
Nutritional information is provided as a courtesy only and should be construed as an estimate rather than a guarantee. Ingredients can vary and Salt & Lavender makes no guarantees to the accuracy of this information. I used ketchup in the nutrition info since my database doesn't have Heinz chili sauce. It's similar in calories, so it gives you a ballpark figure.