  The newly found superconductivity in infinite-layer nickelate superconducting
films has attracted much attention, because their crystalline and electronic
structures are similar to high-$T_c$ cuprate superconductors. The upper
critical field can provide much information on superconductivity, but detailed
experimental data are still lacking in these films. Here we present temperature
and angle dependence of resistivity measured under different magnetic fields
($H$) in Nd$_{0.8}$Sr$_{0.2}$NiO$_{2}$ thin films. The onset superconducting
transition occurs at about 16.2 K at 0 T. Temperature dependent upper critical
fields determined by using a criterion very close to the onset transition show
a clear negative curvature near the critical transition temperature, which is
explained as the consequence of the paramagnetically limited effect on
superconductivity. The temperature dependent anisotropy of the upper critical
field is obtained from resistivity data, which yields a value decreasing from 3
to 1.2 with lowering temperature. This can be explained by a variable
contribution from the orbital limit effect on upper critical field. The angle
dependent resistivity at a fixed temperature and different magnetic fields
cannot be scaled to one curve, which deviates from the prediction of the
anisotropic Ginzburg-Landau theory. However, at low temperatures, the increased
resistivity by magnetic field can be scaled by the parameter $H^\beta
|\cos\theta|$ ($1<\beta<6$) with $\theta$ the angle enclosed between $c$-axis
and the applied magnetic field. As the first detailed study on the upper
critical field of the nickelate thin films, our results clearly indicate a
small anisotropy and paramagnetically limited effect of superconductivity in
nickelate superconductors.
