The nation with its capital as Oslo where a mini-boat launched in 2020 turned up at was Norway.
Oslo is the capital of the Scandinavian nation of Norway which is located in Northern Europe.
In the year 2020, a mini-boat was launched by American students and the tides took it to the North Sea where it was discovered in Norway.
In conclusion, this was Norway.
Find out more on Scandinavian nations at https://brainly.com/question/26268624.