My diet:
Comparison

Sodium erythorbate vs Sodium Nitrite

The short answer
They are not the same salt. Sodium erythorbate is an antioxidant that keeps cured meat pink. Sodium nitrite is the curing salt that prevents botulism. Bacon often lists both.
Side by sideSodium erythorbate (Sodium isoascorbate)Sodium Nitrite
Safety score88/100 Generally safe40/100 Best to avoid
What it isMirror image of vitamin CCuring salt
Main jobKeeps color and slows stale fatsPrevents botulism and keeps meat pink
A nitrite?No ✓ BetterYes
Useful vitamin C?NoNo
Daily limitEFSA: 6 mg/kg; JECFA: none set ✓ Better0.07 mg/kg
Safety score88 ✓ Better40

Swapping one for the other

You can't swap one for the other. The nitrite is what makes the cure safe from botulism. To avoid both, choose fresh meat instead of bacon, ham and hot dogs.

Common questions

Why are both on my bacon?

Nitrite cures the meat. Sodium erythorbate is added with it as an antioxidant. Seeing both names does not mean a double dose of nitrite.