  For $n,m\in \mathbb{N}$, let $H_{n,m}$ be the dual of the Radford algebra of
dimension $n^{2}m$. We present new finite-dimensional Nichols algebras arising
from the study of simple Yetter-Drinfeld modules over $H_{n,m}$. Along the way,
we describe the simple objects in ${}^{H_{n,m}}_{H_{n,m}}\mathcal{YD}$ and
their projective envelopes. Then, we determine those simple modules that give
rise to finite-dimensional Nichols algebras for the case $n=2$. There are 18
possible cases. We present by generators and relations the corresponding
Nichols algebras on five of these eighteen cases. As an application, we
characterize finite-dimensional Nichols algebras over indecomposable modules
for $n=2=m$ and $n=2$, $m=3$, which recovers some results of the second and
third author in the former case, and of Xiong in the latter.
