Not 100% sure but I think I've seen one at the far eastern end of the terminal on ground floor outside.
Also this from Google search. Yes, Tan Son Nhat International Airport (SGN) in Ho Chi Minh City offers luggage storage services, including lockers and storage, located on the ground floor of the International Arrivals Terminal near columns 13 and 14, open 24 hours. Storage rates are approximately VND 27,500 per piece per hour for the first 10 hours and VND 275,000 per article per day for storage over 10 hours. Additionally, third-party services like LuggAgent via Klook Travel offer luggage delivery and secure storage with insurance and convenience.