If you are looking to use the TTW version, then yes, you need TTW and a copy of Fallout 3 with all DLC. Not having them and still trying to activate the mod will lead to the game not starting due to missing masters.
TTW is a mod that aims combines Fallout 3 and NV into one single package so that players can visit both spaces in the same game, and also play FO3 with all the improvements that NV brings.
I do not use it due to incompatibilities, but if you want to try it out, here it is.
https://taleoftwowastelands.com/index.php?sid=3575367400cb6ac261be4e1ff4799d91
HOWEVER, it is perfectly possible to use Drag's mod without TTW or Fallout 3, but you need to use either the Standard or Compatibility version (not both) instead of the TTW version.
Fallout 4 IS NOT required to use the mod. In fact, having Fallout 4 makes no difference whatsoever because the mod already has all the assets it needs, it doesn't touch FO4's files in the slightest. I'm not certain why they list it as a requirement, maybe due to some legal thing since it uses modified assets from FO4, but I wish they wouldn't because it confuses a lot of people who are new to modding.