Maskwood Nexus

The subtype Shapeshifter that appears on the type line is mostly there to reinforce the flavor. A creature card with changeling is just as much an Elf, a Dwarf, a Sliver, a Goat, a Coward, and a Zombie as it is a Shapeshifter.

The tokens created by the activated ability will continue to have all creature types if Maskwood Nexus leaves the battlefield because those tokens have changeling. Other creatures you control will revert to their usual creature types unless another relevant effect is affecting them.

If an effect causes a creature with changeling to lose all abilities, it will remain all creature types, even though it will no longer have changeling. This is because changeling applies before the effect that removes it.