There are no special "Nude laws" in Sweden. The country has a large area in relation to inhabitants, large forests and ten tousands of lakes. You are free to walk around in all forests and take a dip in any of the lakes, if you don't intrude at someones private garden.
Sweden has few personsper square kilometer of land, some 22. In US it's 32, inJapan 340 and Bangladesh 1 078!
At public beaches you need to behave properly and use swim wear, but there are many beaches or part of beaches that are designated for nudists. There are also some nude camping sites.