If Blue Sentinel holds at Power Nexus, can the Power Nexus ability trigger twice and score 2 points?
Ruling: Yes. Blue Sentinel causes Power Nexus's "When you hold here" ability to trigger an additional time, resulting in two triggers. Since the points gained from Power Nexus are not from a "Conquer" or "Hold" action, they are not subject to the once-per-battlefield scoring limitation in Rule 465. You may pay the cost for both triggered instances and successfully gain 1 point from each.
Sequence:
- Blue Sentinel's effect causes Power Nexus's ability to trigger twice
- Both instances are placed on the chain
- You may pay [A][A][A][A] for each trigger to score 1 point per resolution
Nuances:
- Rule 465's "once per battlefield" restriction only applies to points gained through Conquer or Hold actions, not to points from triggered abilities like Power Nexus.