Can a triggered ability trigger during the resolution of another ability on the stack?

Triggered abilities constantly watch the game for their trigger conditions ('when,' 'whenever,' or 'at'). According to CR 603.2, a triggered ability triggers at the moment its condition is met — and that moment can occur during the resolution of another spell or ability on the stack.

However, the newly triggered ability does not go on the stack immediately. CR 603.3 specifies that triggered abilities are placed on the stack the next time a player would receive priority — which is after the currently resolving spell or ability has fully finished resolving (CR 116.5). So the trigger waits in a 'triggered but not yet on the stack' zone until resolution is complete.

Once the resolving object is done, the game checks for any abilities that triggered during resolution (as well as state-based actions per CR 704.3), and then those triggered abilities are put on the stack in APNAP order (CR 603.3b) before any player receives priority.

Concrete example: You activate Goblin Bombardment, sacrificing a Myr Superion. During that sacrifice (part of the activation cost, but the principle is the same during resolution), suppose an effect causes a creature to die during resolution of another ability — if that creature's controller has a 'whenever a creature dies' trigger, that ability triggers during resolution and is placed on the stack immediately after the current ability finishes resolving, before anyone receives priority.

In short: yes, triggers can be 'queued up' during another ability's resolution, but they only appear on the stack once that resolution is complete, per CR 603.2 and CR 603.3.