Hi Anna Lena,
I have to start off by saying that I have no expertise in the area of PT taxation, I have just been doing lots of online research on the topic because I'm toying w the idea of retiring to PT. Tax laws are a moving target and its hard to know what the status is as of 'today', but I've come across a couple of websites that look serious and, even if they may not be 100% up to date, They at least introduce basic concepts of PT taxation. Regarding exemption of IP related income from PT tax, assuming NHR status is applied, this website gives some interesting info, although not super recent -
it says re IP-
"There is an important exception for income from intellectual property. The first €10,000 of this is exempt from taxes and only 50% of the income resulting from own creations is taxed."
so then we would need to know what the PT tax man considers to be income from IP. To my thinking (I work in the publishing industry), that would be royalty payments resulting from for example a publishing contract or for creation of other content (both are related to copyright, which is IP) or for money received from some other sort of licensing arrangement, such as a patent, creatives, or art licensing deal, etc.
I would think that income resulting from providing coaching services would not be considered 'IP'. Unless it was somehow structured that the content is delivered separately from the personal services and separate fees are charged for the two components. Nowadays lots of content is licensed, not sold, so that may qualify for IP income. Just guessing here, though.
And looping back to the issue of the NHR status, how that plays out can also depend on your native tax residency, as the rules refer to the possibility of particular types of income (already) being taxed in one's home country.
Having blathered on about all that, I sometimes see a banner on the expatsPortugal website saying that some company is offering a free tax consult. Probably in the hope of acquiring a paying customer, but if you get your ideas, intentions, and specific questions clear and documented, a brief free consultation might be sufficient to clarify whether the IP exemption would apply to coaching or not.
best of luck with your plans, how ever they pan out!