No, Netflow has no packet sniffing capability.
You might want to look at the new IOS embedded packet capture functionality in 12.4(20T) and later:
Netflow is more of a statistical tool.
Where wireshark actually captures the entire packet of a communication netflows are just a "report" of communications.
Basically after a flow ends the sending device will send information about that communication to a netflow collector. So it would be something like 188.8.131.52 talked to 184.108.40.206 on tcp port 25 for 15mins and transferred 5mb of data.
When you capture flows from a device you can quickly and easily build a good picture of what kind of traffic is going through a deivce and in what quantities.
For example, if you have a T1 that is always at 100% utilization you can look at the flow data and see what Ips are sucking away the bandwidth etc. It is just as useful as a packet capture and in many situations more useful especially when it comes to resource and capacity planning.