A transition between an integer quantum Hall insulator and a chiral spin liquid can become critical without closing the single-electron gap, raising the question of which composite excitations govern the change in topological order. We investigate this question in the SU(3) triangular-lattice Hofstadter–Hubbard model at one particle per site and magnetic flux π/3 per triangle. Using infinite density matrix renormalization group calculations, we identify a weak-coupling integer quantum Hall phase and an interaction-driven SU(3)₁ chiral spin liquid. Near the transition, both the neutral and charge-3e correlation lengths increase substantially, whereas the single-electron correlation length remains short, providing evidence for a Chern–Simons–Higgs critical theory, where a gauge-invariant monopole carries the quantum numbers of a fermionic SU(3)-singlet trion. We discuss the implications for doping the system and recent experiments on doping ν=-2/3 fractional quantum anomalous Hall in tMoTe₂.