SE2419HX, connect to GTX on Laptop

If you have a laptop, the only way to connect a display to the discrete GPU is if your laptop actually has a video output physically wired to that GPU or has a design that allows it to have a BIOS option allowing you to choose which GPU controls the video output.  On most laptops, all outputs are physically wired to the Intel GPU, and the NVIDIA GPU works as a render-only device when needed, using a technology called NVIDIA Optimus.  But Intel GPUs for over 5 years now have supported up to 4K 60 Hz, so the GPU isn't the reason you can't increase resolution beyond 1920x1080.  The SE2419HX itself has a maximum resolution of 1920x1080 60Hz.  Are you trying to get your GPU to render at a higher resolution and then downsample to 1920x1080 post-render?  I don't think Intel GPUs support that, and I'm not even sure NVIDIA GPUs do either, but even if they did, that would not normally be a good idea.  You're going to see scaling artifacts and blur especially on text as a result of rendering at a higher resolution and then downsampling afterward, so the image quality will be lower than it would have been if you had simply rendered at 1920x1080 in the first place.  And if you're playing games or something, then you're just having the GPU do more work to render at a higher resolution even though the end result will only be 1920x1080.  NVIDIA GPUs already have techniques like supersampling to do that more efficiently, and those techniques can be used when the NVIDIA GPU is active, even if the display is controlled by the Intel GPU.

If you want to use a higher resolution, get a display that actually has a higher resolution.