  In this paper we study asymptotic behavior of $n$-superharmonic functions at
isolated singularity using the Wolff potential and $n$-capacity estimates in
nonlinear potential theory. Our results are inspired by and extend those of
Arsove-Huber and Taliaferro in 2 dimensions. To study $n$-superharmonic
functions we use a new notion of $n$-thinness by $n$-capacity motivated by a
type of Wiener criterion in Arsove-Huber's paper. To extend Taliaferro's work,
we employ the Adams-Moser-Trudinger inequality for the Wolff potential, which
is inspired by the one used by Brezis-Merle. For geometric applications, we
study the asymptotic end behavior of complete conformally flat manifolds as
well as complete properly embedded hypersurfaces in hyperbolic space. In both
geometric applications the strong $n$-capacity lower bound estimate of Gehring
in 1961 is brilliantly used. These geometric applications seem to elevate the
importance of $n$-Laplace equations and make a closer tie to the classic
analysis developed in conformal geometry in general dimensions.
