The chart's directory name is charts/

[lindhe]

Having a charts/ directory is a common practice (e.g., see (rancher/charts), but one is not supposed to have that be the chart's directory. The chart's directory name should be the name of the chart according to Helm and is commonly placed inside the charts/ directory like this:

.
└── charts
    └── foo
        ├── Chart.yaml
        ├── charts
        ├── templates
        │   ├── NOTES.txt
        │   ├── _helpers.tpl
        │   ├── deployment.yaml
        │   ├── hpa.yaml
        │   ├── ingress.yaml
        │   ├── service.yaml
        │   ├── serviceaccount.yaml
        │   └── tests
        │       └── test-connection.yaml
        └── values.yaml

[lindhe]

It's even documented in the Rancher documentation how one should structure a chart repo:

https://ranchermanager.docs.rancher.com/v2.7/how-to-guides/new-user-guides/helm-charts-in-rancher/create-apps#chart-directory-structure

(if this repo is indeed a "Rancher chart", which is unclear)