GT 1030 compatible Dell Inspiron SFF ?

Yeah a GT 1030 would likely work in that system, and I see other people online with PCs from that series mentioning upgrading to one. What CPU is in the one that you have?

The power supply is about as low as you can go in terms of capacity, but the GT 1030 has pretty low power requirements, at only around 30 watts (or around 20 watts for the slower DDR4 version). A GT 1030 would be about the only card currently worth considering with that system. Anything more powerful would likely require too much power, and any older cards using similar or less power probably wouldn't be any faster than integrated graphics.