Yes, it tells you about the Nissan distributor with Mitsubishi CAS. It doesn't say anything about whether it works with a Mitsubishi ECU. Your guess is as good as mine. What does the 4G15 distributor matched to the ECU look like and what is the model number stamped on the distributor? Or what year/model of Mitsubishi is the ECU from?

The good news is it will fit into the A15. To fit any Nissan E-series distributor into an any late A-series engine, drill a hole in the shaft, slide an A-series dizzy gear on. Then fix up the hold-down bolt area. This is explained with photos at E15 Electronic Distributor Swap, section "Drill Method - Late Block" is how I would do it.