I’m planning to service my Nissan Juke 1.5 dCi myself for the first time and I’m getting totally confused about oil types. Some places say 5W30, others say different specs and it’s not very clear. I don’t want to damage the engine by using the wrong oil. Also wondering if there’s anything else specific to the Nissan Juke I should change at the same time like fuel filter or any known service items people forget about.

I always tend to use Castrol Oil Selector as a true guide on the specific oil to use (SAE, etc) - Grade is no so important unless you live in a very cold or hot country.
https://www.castrol.com/en_gb/united-kingdom/home/product-finder.html

Mostly, oil and filter are most important service items but overlooked items such as gear oils, fuel, pollen and air filters are equally important and you should find the time to get those replaced individually.