@smartin75, the biggest problem with your question is the word 'hopefully.' As @Sandra51 suggests it would be beneficial for your food safety to use an insulated container and know how long the water would take to heat, etc, via some testing.
The best practice for your scenario is to use a converted cooler as your cooking vessel. Fill it with ice and ice-water and your frozen product. Seal the lot up and put your Anova on icebath function. This will circulate the water in the bath while monitoring temperature. If it rises out of the safe chill mode the unit will give you a notification and click into cook mode. If things don't rise above the chill zone you can manually switch to cook when ready.
There is, however a slight problem with this methodology and that is the time required to heat the volume of iced water to cooking temperature. Provided it takes less than an hour (and it should unless the vessel is too big or over filled with product) all is good. Longer than that, by the time you add in heating time for your cooking product you might slip into risky territory again.