There shouldn't be any problem installing it. Best way to know if any card will work is simply get the dimensions of the new card and measure the length available inside the Omen case. Really all you need to worry about is the length.
But take notice of the PSU required by the new card. I assume your Omen came with a 500W power supply.
If the new card requires more, you will have to upgrade the PSU also. Make sure it has the required power connectors for the card.