This error happens when running a job that requires envoy:
envoy_bootstrap: error creating bootstrap configuration for Connect proxy sidecar: exec: "consul": executable file not found in $PATH
Nomad is trying to execute a consul command and can't find it in its usual location (/usr/local/bin). This happens when nomad is installed for example in /opt. To fix it udate the PATH variable in the systemd service to include the path to consul e.g.:
...
ExecStart=/opt/nomad agent -config={{ nomad_conf_dir }}/nomad.hcl
Environment="PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/opt/nomad:/opt/consul"
...