I consider you’re referring to the “longest chain” the place two nonce are discovered and the respective blocks are broadcasted concurrently. The next is an excerpt from the bitcoin whitepaper describing this state of affairs.
Part 5: Community: Bitcoin Whitepaper
“Nodes all the time think about the longest chain to be the right one and can preserve engaged on
extending it. If two nodes broadcast completely different variations of the following block concurrently, some
nodes could obtain one or the opposite first. In that case, they work on the primary one they acquired,
however save the opposite department in case it turns into longer. The tie will probably be damaged when the following proofof-work is discovered and one department turns into longer; the nodes that have been engaged on the opposite
department will then swap to the longer one”
