Both of these designs have a very significant quirk, in relation to this question: All the guns in their primary batteries are capable of firing forward. Now, there were a few issues (Especially with the Nelson class) of firing all the guns directly forward - But this question assumes these issues have been or can be solved.
The question is simple: Would a line of battleships with Nelson-style configurations have the advantage when their T is crossed?
In most T-crossing scenarios, the ships being crossed are at a disadvantage because their rear weapons cannot fire. In earlier warfare with fixed guns, it was even more devastating because almost all of their guns could not fire. Nelson-style configurations, however, do not suffer from this and can fire all of their weapons on the targets in front of them.
All of those targets which are presenting wide fronts, while each of the Nelson-style ships are presenting narrow fronts.
To be completely fair, I don't envision this as an ideal position for the Nelson-style ships to be in. Their enemy can still fire every one of their guns. However, the Nelson-Style ships don't have the disadvantage that normally comes with having their T crossed, so perhaps the playing field is going to be a little more level.
I am curious as to what sort of things I may be missing out. I'm not a military or naval strategist - My interests lie significantly more on the engineering and technical end of things, so those are the details that stick out to me.
Relevant information: This is targeted at the world I'm building, 50s ish tech where shipbuilding is advanced but aircraft never gained dominance. Battleships tend to be bigger and have bigger guns, but realistically speaking treat the ships as being largely equivalent except for gun placement.