The Nested Input Analysis node receives output from another Analysis that is using a Placeholder Output node. The connection to the Analysis that the Nested Input Analysis node receives data from is made by setting the Analysis to Read parameter within the Nested Input Analysis node's properties panel.
Nested Input Analysis Example
Utilizing Multiple Outputs from a Nested Input Analysis in Nodes that take multiple Inputs
If you are using a Nested Input Analysis that receives fields from multiple Placeholder Output nodes, the Nested Input Analysis node will create an outgoing port for each Placeholder Output.
If you then attempt to connect these outgoing ports to a node that accepts multiple inputs, you will find that only one of the fields is carried over.
For example, this issue could occur when attempting to connect all outgoing ports from a Nested Analysis Input node (that contains multiple outgoing ports) to a Nested Analysis Output node.
The workaround to this issue is to gather fields from outgoing ports with Select nodes.
For example:
Using Select nodes, you can collect the fields that the Nested Analysis Input node receives from each of its Placeholder Outputs nodes. You can then use the Select nodes as inputs to a common node, where all of the fields can be used.