Hello, fellow players! As a newbie to the game, I've found this forum to be extremely helpful in getting me going on the right track - glad to be a part of this community!

I've just finished my first playthrough of D2X (Normal difficulty) - what I'm wondering is, if I were to replay/continue the game again (same character) on Normal difficulty for the secret cow level, will I be able to immediately continue to Nightmare after I'm done? I actually intend to play the game on Nightmare without having to go through the whole thing on Normal again.

To elaborate;
After clearing the Secret Cow Level, would I have to go through Acts I-V again to carry on to Nightmare, or could I simply exit back to the menu and continue off from there with all the loot I've earned? If not, are there other alternatives - say being able to teleport to the final checkpoint and simply finish off Baal again?

Thought I'd ask around before risking it and trying it out myself. Pardon me if this has already been answered time and time again, I couldn't find anything from searching. Thanks in advance.