I might would do it if I were feeling adventurous and foolhardy. But I would probably be hesitant to do it, and I have always been a high roller on tight connections. I'd say it is theoretically possible. If everything went smoothly you would 'probably' make it. However MNL is not an airport where you can depend on everything going smoothly. Once you clear immigration in T3 and get your baggage you can hop in a taxi to T1 and get there fairly quickly. But I assume this is NW72. It is a madhouse checking in for that flight and exit immigration is usually quite time consuming as well that time of the morning. I think you can use OLCI now which would help but still need to re-check at NW's check-in counter.