  We examine transport in a holographic model which describes, through a
nonlinear gauge field sector, generic nonlinear interactions between the charge
carriers. Scaling exponents are introduced by using geometries which are
nonrelativistic and hyperscaling-violating in the infrared. In the dilute
charge limit in which the gauge field sector does not backreact on the
geometry, a particularly simple nonlinear theory reproduces the anomalous
temperature dependence of the resistivity and Hall angle of the cuprate strange
metals, $R \sim T$ and $\cot\Theta_H \sim T^2$ while also allowing for a linear
entropy $S \sim T$, and predicts that the magnetoresistance for small values of
the magnetic field $h$ should scale as $\sim h^2 T^{-4}$. Our study lends
evidence to the idea that the strange metal behavior of the cuprates relies
crucially on the linear temperature dependence of the entropy.
