I found two Cisco drivers: Cisco Manager & Cisco Nexus. As it looks like the Cisco Nexus driver shows less metrics than the Cisco Manager driver, on the other hand Cisco Nexus exposes parameters Cisco Manager does not support.
Can I run both drivers in parallel?
The Cisco Nexus driver supports NX-API, which is only available in Cisco NX-OS (e.g. Cisco Nexus 9000 series). The Cisco Manager driver should be used for Cisco devices that run Cisco IOS, IOS-XR and IOS-XE.
It is true that currently the Cisco Nexus driver supports less parameters than the Cisco Manager, but it should not be a problem to update this driver if required.
Can you run both drivers in parallel? Technically nothing stops you of running two elements (each one using a different Cisco driver) pointing to the same Cisco device. As long as the SNMP agent is running on the Cisco device, you will be able to poll the data from both elements. However, it is not advised to poll twice the same device because it could potentially cause performance issues.