Rather than using water with zero flavor, add a can of tomato sauce and let it cook down.
I would also suggest putting half of the packet in at the beginning of the browning so there's a bit of bloom in the spices, then add the tomato sauce and the rest of the pack at the end of the process. Simmer until it's all a thick sauce.
Well done sir, not using the cardboard taco shells is worth bonus greens....if I had them.