baking soda and/or baking powder is used in some shortbreads - mostly in biscuit type products.
no clue where the sodium nitrate comes in, that's not in any of my leavening agents.
most breads use yeast as a leavening agent. the yeast eats sugars and poops/generates CO2; gluten development in the flour makes the dough elastic - creating 'balloons' of trapped CO2 gas.
there's certain some exceptions - but for the most part over-working the dough _especially_ after the last rise prior to baking (could be 2 or 3 rises...) "deflates" aka breaks the CO2 balloons.
bread at the basic is flour, water, yeast. salt is optional as is virtually everything else "in the purest sense"
the proportions and the technique play a huge role in how a loaf of flour+water+yeast turns out.
ciabata, for example, is a very 'wet' aka 'slack' dough - that is the % of water to the % of flour is 80%+.
again a generalization, but 'wetter' doughs aka 'higher hydration' typically develop bigger holes/bubbles. a dough you mix / knead for 20-30 minutes is not likely to develop big holes - the 'crumb' aka 'texture' of the bread will be much finer.