Never I say never use gasoline oil in a diesel engine. Buy diesel oil made for diesel engines. You don't have to buy deck sauce. There are plenty of places that sell oil for diesel engines. But they have different specifications and you shouldn't use gasoline engine oil in diesels or diesel oil and gasoline engines for that matter

Posted by: @nickwantsatoyota

I have a 2017 chevy cruze diesel 1.6L. It takes a very expensive 5w30 Dexos2 rated oil that is twice the price of any other 5w30 you can find on all shelves. Can I just use full synthetic 5w30 that is good in all gasoline engines and stop having to order the special AC Delco oil that literally no one carries in stock except a dealer or RockAuto? 

The piston rings on diesel engines are way more robust and durable than piston rings meant for gas engines. Gas engines have compression ratios of about 9 to 10:1, diesel engines have compression ratios as high as 22:1; simply compressing the air rapidly ignites the diesel, it's not initiated by a spark. They have very different operating parameters as a result. You can't skimp and operate a diesel engine. 

If you want the Dexos-certified stuff specified in the owners manual your options are the AC delco (which is relatively inexpensive on Rock Auto as you say) or Mobil 1 (which is what I run in my truck; good oil but expensive).

But by now, I assume you are off warranty.  If so, you don't have to get Dexos-certified oil.  Any good 5w-30 diesel oil (like Rotella) should be OK.