First, carbon taxes, when they have been enacted they have not been effective. And there are massive barriers to enacting them, because there is no constituency that advocates for them. The progress we have made with reducing emissions has been through industrial policy of various sorts, rather than through single taxes. For every problem, there is a solution which is simple, obvious, and wrong. And I think that the history of carbon taxes has shown them to be this obvious and unfortunately wrong solution.
Similarly, baseload, or more properly firm energy supply, can come from all sorts of carbon free sources. From storage (hydro or battery), to geothermal, to advanced geothermal, to hydrogen, to ammonia storage, to who knows what will be developed over the next few decades. We have a rich portfolio of solutions, and most of them are reducing in cost quickly. However nuclear is not reducing in cost, and it's not clear that it will ever be able to compete again. Attach 12 hours of storage to a solar array and you'll get a "baseload" source, and it will be cheaper than new nuclear.