  In arXiv:0908.4089, we have proposed a model where natural inflation is
realized on a steep potential as a consequence of the interaction of the
inflaton with gauge fields through an axion-like coupling. In the present work
we study the nongaussianities and the spectrum of tensor modes generated in
this scenario. The nongaussianities turn out to be compatible with current
observations and can be large enough to be detectable by Planck. The
non-observation of tensor modes imposes new constraints on the parameter space
of the system that are about one order of magnitude stronger than those found
in our previous work. More importantly, in certain regions of the parameter
space tensor modes might be detected by upcoming Cosmic Microwave Background
experiments even if inflation occurs at energies as low as the TeV scale. In
this case the tensor modes would be chiral, and would lead to distinctive
parity-violating correlation functions in the CMB.
