Just check all your hoses for tightness and I believe the radiator reservoir is on that side also along with the waterpump, it's hard to say what it is without being able to see your problem. The car should still be under warranty so you should take it to the shop.
A small radiator leak can cause antifreeze to leak on your 1998 Chevy Lumina when there are not any spots on the ground. A pinhole in a hose can also cause this.
antifreeze lines
your heater core is leaking
usually caused by a leaking heater core.
fix it
Find the source and repair it.
Possible leaking hoses or water pump
If there is coolant coming from it and it isn't a hose.
They use Dex-cool from the factory.
DEX-COOL (50/50 mixture)
Leaking radiator? Leaking or loose radiator hose?
You have to use Dexi cool anti freeze it works best for all Chevy impalas