Your inner loop must reset position after value 25 (or 26 English alphabets), back to value 0 (or back to letter A) . And this condition will trigger every time outer loop limit is > 26.

Here is the draft code:

Let Outer_Limit = 50 (dynamic and can change all the time)
Let alphaArray = {‘A’,‘B’,…‘Z’} (number of alphabets is fixed at 26)
Let index=0
For X = 0 to Outer_Limit-1
if index>Length(alphaArray)-1 then
'when loop runs
'first time this condition will be true when index reaches value 26. Here X=26, and index = 26
'X can continue all the way to 50, but index has to restart from 0 so that it can return to letter A
index=0
else
’ this condition will be true as long as index is between 0 and 25 .
index=index+1
end
'when you reach here index will be any value between 0 and 25
'X can continue to keep incrementing as usual
Let thisLetter = alphaArray(index)
Let thisName = “Name”+thisLetter+X.toString()
Next X