No, not with supported methods.
In an Alarm that has an eMail action, you can add a number of variables in the email body the Alarm sends out.
See the ActionParameter enumeration.
When you define an Alarm to trigger a RunScriptAction you could in that script do whatever PowerCLI is capable of doing.
Including retrieving Tags.
Now the problem is that by default this script will have to be uploaded and run on the VCSA.
And if you want to use PowerCLI you would have to install PowerShell and the PowerCLI modules on the VCSA.
Which is officially not supported!
There are a number of semi-official ways around this.
One runs a minimal script on the VCSA in a language that is available by default on the VCSA.
That minimal script then triggers the real script on a separate server.
Kamen wrote a blog about this method, see Use-Case: Execute PowerCLI Scripts as vSphere Alarm Actions using Script Runtime Service
Kamen uses SRS as the remote server to run the PowerCLI script, but this could be whatever reachable server where you run PowerCLI.
A method I prefer, since it doesn't require anything on the VCSA that could jeopardize your support, is to use SNMP traps.
An Alarm can generate an SNMP trap with the SendSnmpAction.
Now on your SNMP Server you can intercept that trap and take action accordingly, i.e. run a PowerCLI script.
As you can see, nothing to support referring to Tags directly in the official Alarm methods.
But there are a number of workarounds, some of which require installing additional servers.