Counter Mode with a sequence of zeros bits plaintext, is it secure?
This all depends on the IVs. If they are independently generated, the IVs will not only be different (so $IV_1 \neq IV_2$), but also their sequences will not overlap with overwhelming probability. In that case,  then everything should be fine, so $C_2 = E(K,(nonce,IV_2))$, and $C_1 = M_1 \oplus E(K,(nonce,IV_1))$. 

However, if they are reused (so $IV_1 = IV_2$), then $C_2 = E(K,(nonce,IV_2)) = E(K,(nonce,IV_1))$, so $C_1 = M_1 \oplus E(K,(nonce,IV_1)) = M_1 \oplus C_2$, and therefore $M_1 = C_1 \oplus C_2$.