  We study the effects of quasiparticle interactions on disorder-induced
localization of Dirac-like nodal excitations in superconducting high-$T_c$
cuprates. As suggested by the experimental ARPES and terahertz conductivity
data in $Bi_2Sr_2CaCu_2O_{8+\delta}$, we focus on the interactions mediated by
the order parameter fluctuations near an incipient second pairing transition
$d\to d+is$. We find interaction corrections to the density of states, specific
heat, and conductivity as well as phase and energy relaxation rates and assess
the applicability of the recent localization scenarios for non-interacting
random Dirac fermions to the cuprates.
