In a large microwave safe bowl combine the sweeteners. Whisk together until fully combined. Make sure the bowl is large enough this mixture bubbles a lot while cooking
Add the syrup, condensed milk, and vanilla. Whisk to fully combine
Add the butter. Microwave on high 1 1/2 minutes. Stir until butter begins to melt. Microwave on high in 30 second interval until the butter is completely melted and sweeteners are beginning to dissolve. (Mine took 3 minutes total) Watch carefully the mixtures bubbles up a lot while it is cooking.
Use oven mitts to remove the bowl from the microwave. The bowl will be hot. Use a fork and stir for at least 30 seconds or until the sweeteners are fully dissolved
Microwave on high for 2 to 5 minutes or until bubbly and slightly sticky. Times vary depending on microwave wattage and the type of bowl. (Mine took 4 1/2 minutes)
Stir and carefully fold in the nuts (if using). Set aside while making the nougat