The easiest way is to install a Picatinny rail on top of the receiver. It's already drilled and tapped for it. You can buy them off eBay for $4 or $5. The same rail that fits a 500 or 590 will work on the 930.
NOTE: Be sure the screws (particularly the front ones) don't extend too far into the receiver. The front ones should be flush inside the receiver.
Thank you for the heads up. I did not think of that being a problem. I planned to use almost any red dot sight. Do you have any suggestions, or a list of sights that work with the factory stock?
The 930 SPX is a good reference for a maximum height that most can get a good cheek weld with. The iron sights on the SPX will co-witness with most micro dots on the rail. (Trijicon RMR, Leupold Deltapoint, Burris FastFire, Vortex Venom.) These work well on the rail with the factory rise set at the maximum inside the stock. Tube style red dots like the Vortex Sparc or Spitfire are too tall. Mossberg does make a monte carlo style stock used on their slug guns that can be sourced for the Tactical that might open up more possibilities for you.