I've always got the impression that Nenshi was only about cities; so any move would have to be related. I don't agree with the rhetoric that moving provincially or federally is somehow a promotion. Nothing he has said would suggest he thinks it would be "the next step" or whatever either. IMO anyways
Perhaps if the Federal Government ever decides to get back involved in public housing or a substantial pivot towards municipalities like they were in the 60s - 80s there would be some positions that an urban-minded mayor would be suited for or interested in. I don't see that pivot happening, the Feds have generally been in retreat from urban issues (excluding the recent blip in infrastructure spending).
I am excited for him to continue. Calgary is a big, cumbersome vessel to change course from a sleepy, suburban, prairie town to an increasingly important, powerful, diverse city-region. Such a transition benefits from a steady, progressive - but pragmatic - hand on the wheel and so far we have gotten that from the Nenshi era. Urban reform (from a urban planning, development, lifestyle and cultural perspective) is slower than I would like - but it has also been accomplished without much blowback or backsliding. We are finally seeing some changes on the ground from the last decade of reform. Continued pressure in that direction for another 4 years will help cement the new direction into more policies, regulations and processes to keep the snowball growing in the right direction.
I am more worried about another term of non-thinking ideologues such as Chu than I am worried about another term of an opinionated - but compromising and intelligent - Nenshi.