He has chakra; every living thing has it.
And he has a chakra flow.
Gai stated that he has no talent for ninjutsu or genjutsu; that's the only thing which is close to an explaination; but i want to know why hopefully Kishi explains it.
But everyone has a differnt level of talent when it comes to chakra; for ex. Sakura had better chakra control than others so she can use her chakra control to increase her strength.
I think he has chakra and he can control it in a level; in databook stats; he has points on nin-genjutsu and handseals even for a little and he can walk on water, but he can not convert it in higher levels.