The 130 Kw generator can't provide enough juice to run a 250 Kw motor continuously. What it can do is charge the 92 Kwh battery and use that to turn the motor for a while. Problem is; it will take less gas to provide the HP directly than it will to add an extra step consisting of charging a battery. Something I always hear is how a gas engine running at it's peak will be more efficient and that is true BUT. Notice that the leading experts on hybrid tech never run the gas engine for the purpose of charging the battery. They run it to propel the vehicle and usually charge the battery with regen braking or left over energy from gear reduction in the planetary. Also consider that weight costs energy to move and this pickup is likely to have a battery pack that will weigh around a thousand pounds. Speed costs range and so does weight. What the guys at Stellantis are basically proposing is a Chevy Volt platform under a pickup body. The Volt did pretty much the same thing, with an electric motor drivetrain driven by either the battery or gas generator. GM abandoned the platform and I think for a good reason.  
As for how much HP a gas or diesel engine will need to run a 130 Kw generator, maybe ask an irrigator how big an engine it will take to replace a 175 HP electric motor running an irrigation pump.