Generally, yes, for external inhalation use in a sealed product — but "natural" doesn't mean risk-free, and a few groups should be more careful than others.
Where the real risk is
Skin contact (undiluted oil can irritate; some citrus oils are photosensitizing), ingestion (not meant to be swallowed), pets (several oils are unsafe for cats especially), pregnancy/medical conditions (ask a doctor first).
What a sealed inhaler changes
No open oil, no skin contact, no ingestion risk by design — removes two of the four risk categories above by construction.
Who should be more careful
Known fragrance sensitivities or migraine triggers → introduce gradually, stop if you notice discomfort.
What "100% natural" doesn't mean
Not hypoallergenic, not risk-free for everyone — natural describes the source, not a guarantee for every individual.