Looking at Krattenthaler's famous "determinant calculus" surveyKrattenthaler's famous "determinant calculus" survey (also, suggested by Per Alexandersson) we find Theorem 26 in there, which answers a more general question, and should (most likely) yield the claim in the OP.
Theorem Let $q$ be a nonnegative integer, and let $L_1,\ldots,L_q$ and $A, B$ be indeterminates. Then, \begin{equation*} \det\left( \binom{BL_i+A}{L_i+j}\right) = \frac{\prod_{i < j}(L_i-L_j)}{\prod_{i=1}^q(L_i+q)!}\prod_{i=1}^q\frac{(BL_i+A)!}{((B-1)L_i+A-1)!}\prod_{i=1}^q(A-Bi+1)_{i-1}, \end{equation*} where $(a)_k$ is the usual Pochhammer symbol.
The matrix in the OP is given by \begin{equation*} M_{ij} = \binom{q^2-1}{q(i-1)+j-1}, \end{equation*} thus we can select $A=q^2-1$, $B=0$, $L_i = q(i-1)-1$, and apply the above result, and hopefully things fall into place.