Lava not negate fall damage, contrary to Water.

Fall in Lava and touch the bottom inflict fall damage, the only way to negate fall damage is to hold the space bar and the Lava pool need to be 3 blocks atleast.

This is boring because you can't negate fall damage in the Nether if you don't have cobweb (or Slime block) because you can't use the Water in the Nether.
(MLG Lava Bucket)