It’s actually detecting your Nvidia encoder but your profile is invalid so it disables any automatic adjustments.
If your profile handbrake-video contains encoder nvenc_h264, i.e. your profile is already set to use the hardware encoder. MCEBuddy is looking for either a software encoder, x264, to automatically enable its hardware adjustments or the handbrake-UsingHardwareEncoding=true directive in your profile which tells MCEBuddy that the profile is already optimized for hardware encoding and it shouldn’t change anything, just execute it, so it ends ups being an invalid profile.
Either switch the encoder to the software encoder in the profile or add the handbrake-UsingHardwareEncoding=true directive