No, generally 1. d4 Nc6 is inferior to other defenses that black has. I would have followed up with c4 probably (as 5 on the 2nd move seems a bit premature in this opening). The knight is misplaced on c6 anyways. However, I am a QG/ 1. d4 (d5/Nf6) 2.c4 player.
To answer your question however, the reason is that Nc6 (N-QB3) is not a counter to your stonewall attack setup! Simply continue with your normal moves- In this opening I believe the knight is also misplaced on c6 as well since black should not block his c-pawn-(a rule of thumb in most d4 openings). That c pawn needs to be at c5 in order for black to pressure your center/ d4 pawn as you have probably learned through your reading of the system. In addition, the ideal setup for black would be to somehow post knights on f6/ d6/ where they pressure the weak e4 square. This is likely why Nc6/N-QB3 is not covered in your book.
So basically, as you are a stonewall attack player, d5 was the wrong idea (imo, others opinions may differ) and you should have continued with the normal stonewall setup. For this opening, ideas are important more than theory.
On a side note...since you are a stonewall attack player, I suggest you learn the Dutch Defense Stonewall Variation which is a Stonewall for black. Unlike the stonewall attack, this system has been played by good attackers such as Botvinnik. I hope my reply helped 
and by the way you accidently made 2 threads on the same topic.
I am learning to use the Stonewall attack and I want to know what are the ideal defenses for black. I was playing my father today and I opened with the traditional stonewall P-Q4 and then he countered with N-QB3. So I advanced my Q4 pawn attacking the knight.
But My stonewall formation of my pawns was broken. I've been avidly reading a book dedicated to the stonewall and I have seen counters for black N-KB3 or K-4 but never N-QB3. Is there something I'm missng. Keep in mind I am a beginner learning new openings. Is this a good defense for black or an easy move for white to attack
Thanks