Also,
DO NOT drop the water level below the eggs! The eggs should NOT be exposed from the water at any point in time. (Even people that move eggs put the container into the water and scoop the eggs into the container, you don't pull the eggs out of the water.

)
If you're careful with the waterchange you won't wreck the bubblenest. Dino and I have done waterchanges on
betta tanks while they had bubblenests and done just fine.
Don't create more current than necessary to pull the water, and be slow when pouring it back in.. you should do fine.

(If you pour water back into the tank against the glass it should thwart some of the disturbance.)