In Black Clover, how is Nero able to find the magic stones? I have been watching Black Clover from the start and was interested in the bird (which later became his pet name Nero) from the start and followed him on his head from the time he joined the Black Bulls squad. I knew they said in the start of episodes that these type of birds stick to a person having low mana.

The bird Nero, seems to be able to point important things to Asta, like finding him the magic stone in an underwater temple and mostly helping him point to something important. My hypothesis is that he could have some sort of mystical powers to maybe.

How is the bird (Nero) able to point out important things to Asta?
Your hypothesis is in the right direction, though the powers don't seem to be very mystical, just unusual in his species.
Nero is of the species known as Anti-Birds which the wikia describes as:

Anti-birds are small birds that have black feathers on their back, wings, and around their face. Their faces have red feathers while their undersides have white feathers. Their beaks are black and they have a pair of feather that are shaped like downturned horns.
The Anti-birds are capable of sensing mana and will peck at those with low or no mana. Anti-birds will not approach anyone with high levels of mana and will become frightened when they get close to those with powerful mana

(emphasis mine)
The wikia entry for Nero lists this mana sensory ability as what allows him to detect magical items and and help them navigate toward a source of mana. This utilization of the mana detection seems to be unique to him, as the wikia also mentions the following ways in which Nero differs from usual anti-birds:


Nero is the only Anti-bird that has upturned horns and two tail feathers shaped like arrows

Currently only Nero is shown to be able to detect magic stones and Anti Magic weapons



As you can see, there's no clear confirmation or reason why Nero is different than the others, but we do know that he is the only one who can do this.