Even with a 15 gauge angled nailer i find it quite difficult to get a nail
in on a sufficient angle on the 2nd last board going with the tongue towards the wall, so as not to not split the tongue or to obstruct the joining of the two pieces because the nail is in to vertically...

3rd from last board no problem with the nailer fitting when the pneumatic stapler wont..and face nailing the last where it is hidden by the baseboard..

any help would be appreciated..

Wood glue the tounge and grove and sub-floor glue it down, clamp and wait for it to dry. Or top nail. No othe option if you want to keep the flooring "tight".

You may also be able to predrill holes and hand nail into the tongue.

I have a rather inexpensive but good Ryobi drill press that helps a lot with blind nailing using a 3/64" bit.

You can easily make a simple jig using two boards cut 3" x 4", screwed to a base plate 4" x 4". Mark the two boards and cut a notch from top corners down so that you can place a plank of flooring across the two boards and the plank is held at a 45-degree angle to the drill bit on one side; flip the jig around and a steeper thirty-degree angle can be achieved. Cut a slot in the base plate and use a carriage bolt to secure the jig to the drill press so that it can be adjusted for ripped planks as well. It is quite simple to align the bit with the tongue and lock the jig down. There will be enough flat area on top of the jig that you don't have to remove it when straight-drilling for face-nailing; simply lower the drill press table.

Anyway, it is simple to drill pilot holes in multiple planks in a very short amount of time.

Make sure you soak your nails in 3-in-1 oil or dip them in parafin.

Parafin is probably the best choice for top-nailing. I have found that oil tend to darken the wood around the set nail. Even though filler would hide the hole, the dark ring shows up.