  The Nuclear Stellar Disc (NSD) is a flattened high-density stellar structure
that dominates the gravitational field of the Milky Way at Galactocentric
radius $30\lesssim R\lesssim 300$ pc. We construct axisymmetric self-consistent
equilibrium dynamical models of the NSD in which the distribution function is
an analytic function of the action variables. We fit the models to the
normalised kinematic distributions (line-of-sight velocities + VIRAC2 proper
motions) of stars in the NSD survey of Fritz et al., taking the foreground
contamination due to the Galactic Bar explicitly into account using an $N$-body
model. The posterior marginalised probability distributions give a total mass
of $M_{\rm NSD} = 10.5^{+1.1}_{-1.0} \times10^8 \,{\rm M_\odot}$, roughly
exponential radial and vertical scale-lengths of $R_{\rm disc} =
88.6^{+9.2}_{-6.9}$ pc and $H_{\rm disc}=28.4^{+5.5}_{-5.5}$ pc respectively,
and a velocity dispersion $\sigma \simeq 70$ km/s that decreases with radius.
We find that the assumption that the NSD is axisymmetric provides a good
representation of the data. We quantify contamination from the Galactic Bar in
the sample, which is substantial in most observed fields. Our models provide
the full 6D (position+velocity) distribution function of the NSD, which can be
used to generate predictions for future surveys. We make the models publicly
available as part of the software package AGAMA.
