Naruto's Sage Technique is just a free form energy with which he manipulates the wind-natured chakra in Rasengan to create Rasenshuriken. However, it used to be the case that he only managed to create maximum of 2 Rasenshurikens by adding his wind chakra before his Sage Mode came to an end.
If he is granted unlimited chakra from Kyuubi, can he create unlimited number of Rasenshuriken?
No, I don't think so. I believe that Kyuubi's chakra isn't unlimited.
First, Kyuubi cares, that Naruto wastes it's chakra. Second, Hachibi's fight against Sandaime Raikage suggests, that the chakra of a beast isn't unlimited, because Hachibi was knocked out because of exhaustion. Because the beasts are pure chakra, I think that would mean, that it has too less chakra.
The Kyuubi's chakra definitely is not unlimited. And there's a limit to how much Naruto can use it.
The Kyuubi tells Naruto on more than one occassion that he's being reckless with his chakra. The Kyuubi also looks older when Naruto first takes his chakra. Finally, if Naruto uses too much of the Kyuubi's chakra the Kyuubi's chakra take over Naruto.
There's no way to get unlimited rasen-shuirken at this present time.
Now, Naruto is able to create life, redirect energy flow and do many things he could not do just with the kyuubi. He is also now the jinchüriki of all the bijü.
So yes, I think now, he could create infinite rasen-shüriken if he so wished
