  Vector magnetometry is an essential tool in characterizing the distribution
of currents and magnetization in a broad range of systems. Point defect
sensors, like the nitrogen vacancy (NV) center in diamond, have demonstrated
impressive sensitivity and spatial resolution for detecting these fields.
Measuring the vector field at a single point in space using single defects,
however, remains an outstanding challenge. We demonstrate that careful
optimization of the static bias field can enable simultaneous measurement of
multiple magnetic field components with enhanced sensitivity by leveraging the
nonlinear Zeeman shift from transverse magnetic fields. This work quantifies
the trade-off between the increased frequency shift from second-order Zeeman
effects with decreasing contrast as off-axis field components increase,
demonstrating the measurement of multiple components of the magnetic field from
an exemplar antiferromagnet with a complex magnetic texture.
