Starting a Nintex Component Workflow from Microsoft Dynamics is made simple by Flow actions. You start this process by first copying the API URL from within Nintex Workflow Cloud. 

Next you transition over to Micosoft Dynamics and choose to create a new Flow from the entity you wish to initiate the NWC call from.

This will route you to the Flow designer where you can add an "HTTP + Swagger" action. This is a premium dynamics action and may incur addition licensing cost. 
 

Within the "HTTP + Swagger" action, you can paste your API URL from NWC. 

Pasting in this URL will automatically make your component workflow visible and create fields for the content needed in the body of the Http action. From here, you simply need to insert dynamic or static content into these fields so dynamics can forward this to the input variables for the component workflow.

Once you save this flow, you can run the http action directly from your dynamics entity and call the component workflow instantly.