No, those theory lines are small positional nuances and complicated strategic plans. I would recommend to simply play castle then d5 and c5. Black's position is more active than in the Queen's Gambit due to superior development and you get a first taste of those typical d4 positions.
Nimzo-indian

If you wish to play the Nimzo, then you will need to learn the QID as well or something similar to deal with white playing Nf3 instead of Nc3. This will happen as you impove and play higher rated opponents. This also means doubling your workload as far as knowing opening theory.
The Tarrasch is also a quality defense against 1.d4.
If you like tactics, then the KID is also a viable choice.
No matter which mainline defense that you choose against 1.d4, you will have to also contend with the London, the Colle, the Veresov, and the Torre attack. That's just reality.
Im trying to learn the nimzo indian, but there seems like there is a ton of theory. For a 1200 like me, is it worth it for me to try to learn all that? Also, the only learning I've done were a few lessons, a gothamchess video, and I used the chess.com analysis to look at some moves.