Having seen his team go behind in the first half to another new boy, Lee Miller, Jimmy Calderwood's troops stormed back in the second period and were unlucky not to shade it in the end.
With a near capacity Tannadice basking in sunshine, the vociferous Dons support were first to cheer when their team created a hatful of chances in the opening minutes.
But it all came to an abrupt halt when United struck gold after seven minutes when that man Miller opened the scoring with a close-range shot.
Mark Wilson's deep corner was met by David McCracken but the defender's weak shot fell to the striker, who wheeled round and curled the ball high into the net from six yards.
Aberdeen were back on level terms three minutes after the break thanks to a great goal from Nicholson. A wonderful chipped pass from Kevin McNaughton found the midfielder ghosting in behind the United defence to slot the ball home from ten yards.
With the clock ticking away and having created a number of chances, Jamie Smith turned Mark Kerr and chased towards goal.
His low cross created panic in the home defence but somehow substitute Garry Kenneth cleared the ball to safety, much to the relief of the Tangerine faithful who, at the end, were the more grateful for the point.