Two different Kelvin Probe Force Microscopy (KPFM) measurement configurations have been combined to evaluate at the nanoscale the effects of an electrical stress on Organic Thin Film Transistors (OTFTs) properties. As an example, Channel Hot Carrier (CHC) degradation has been induced to provoke some damage in the studied devices. The results show that the use of the two KPFM configurations, together with their nanoscale resolution, provides additional information about the damage in the different regions/materials of the devices, allowing to correlate device level characteristics with the nanoscale material properties.