With some slightly less cold weather in the weeks before Feburary 1658 Denmark-Norway is likely to remain a great power with strong overseas interests.
With full control over Oeresund the King will have plenty of cash and is likely to finance expeditions. Could very well be Danish-Norwegian explorers opening the South Pacific and claim the two big islands east of the new continent - named Ny Jylland (New Jutland). The northen island is called Ny Fyn (New Funen) and the southern Ny Sjælland (New Zealand) - all together Ny Danmark (New Denmark).
New Jutland is sold to GB in 1823, as the Danish-Norwegian foreign policy is hinged on good reklation with teh British Empire. The islands remain Danish however, but with only a few thousand settlers. A story has it that the Danish-Norwegian delagation at the conference simply put a hand on map where Ny Fyn and Ny Sjæalland was and thus avoided further British interest.
Next we have Denmark-Norway immigrants be unwelcome in America in late 19th century and early 20th century. Say beacuse Denmark-Norway somehow got involved in the American Civil War on the loosing side. So in the next decades hundreds of thousands of Danish and Norwegian immigrants mainly go to Ny Danmark. By early 20th century New Denmark gain equal rights as part of the Kingdom, and soon has a population and economy equal in size to Denmark or Norway, making the Triple Monarchy a rather odd but quite stable nation.
Regards
Steffen Redbeard