Let $i: X \to N\mathcal C$ be a monomorphism in the category of simplicial sets, with $C$ a category and $NC$ its nerve. I am looking for sufficient conditions (and not too difficult to check) under which this monomorphism is a Joyal equivalence.

A sufficient condition I know is to apply $\mathbb C$, the adjoint of the homotopy coherent nerve and check that $\mathbb C(i)$ is a Dwyer-Kan equivalence.

Since $C$ is a category, $\mathbb C NC$ is DK-equivalent to the discrete simplicial category $C$, thus one should find conditions under which $\mathbb CX$ is also discrete.

For the $\pi_0$ condition, one can use the fact that $(\pi_0)_* \mathbb C \cong h$, where $h$ is the adjoint to the classical nerve, and relatively well understood.

Is there any known way of computing the fundamental group and/or the homology of the hom spaces of $\mathbb C X$?