Can You Play 2DS Games on a DS Lite? No

No.

• Hardware mismatch: 2DS uses a single LCD (split by bezel) and ARM11 CPU; DS Lite has dual separate screens and ARM9/ARM7.
• Cartridge incompatibility: 3DS/2DS game cards have a physical tab preventing insertion into DS/DS Lite slots.

Reverse works: All DS games play on 2DS/3DS (backward compatible).