Why did Moshe add the word "ha'Nosarim"?
Rashi: It insinuates that Elazar and Isamar survived the decree to die due to Aharon's participation in the sin of the Golden Calf. 1
Rashi (in Chagigah, 11b): They too, deserved to be burned, and they were spared only because Hashem took pity on Aharon.
Which Minchah is "ha'Minchah" referring to?
Rashi: It is referring to Minchas Shemini and the Minchah of Nachshon. 1
Why did Moshe see fit to instruct them to eat them?
Rashi (Pasuk 19): Because, although a Kohen Gadol who is an Onein is permitted to bring Korbanos, he is not permitted to eat them.
Seeing as all S'tam Menachos are brought as Matzos, why did he need to add the word "Matzos"?
Rashi: Because this Minchah was unique, inasmuch as it was a one-time Minchas Tzibur.
QUESTIONS ON RASHI
Rashi writes that Nadav and Avihu were already Chayav Misah due to Chet ha'Egel. R. Eliezer says that they were liable for ruling in front of their Rebbi!
Moshav Zekenim: At Chet ha'Egel, it was decreed that they die prematurely. Because they ruled in front of their Rebbi, they died now.