Small dogs — Chihuahuas, Yorkies, Pomeranians, Mini Dachshunds and similar breeds (typically 5–20 lb) — only need around 150–550 kcal per day. Following the 10% rule, that means just 15–55 kcal of treats daily.
That's often only 2–6 small training treats per day. Larger biscuits can exceed a small dog's treat budget in a single piece, so always check the calorie count on the package.
Treats should never replace meals. The remaining 90% of daily calories should come from a complete and balanced diet for healthy weight and nutrition.