Champions Program is not the right place to post such a question. This place is only for Champions program content and applications.
Now, on your question. This is not much of a nurturing stream, but more of an activation campaign for cold leads. You can use any of the 3 mechanisms (batch smart campaign, trigger smart camapign or engagement program), although I would not use a trigger in this case because you do no need the campaign to start at the very minute the lead is created in the DB.
Pros of batch campaign: you can set different time intervals between each cast, using wait steps. Cons: it's harder to add / remove / change the order of content when some leads are in the middle of the flow.
Pros and cons engagement programs are exactly the opposite.