While he feigned nonchalance, it was obvious he was as proud as a kid with a new toy to show them what he'd discovered.
His nonchalance made her angry.
Her instincts didn't like Evelyn's nonchalance on the subject.
He sat down in his chair and propped his legs up with nonchalance, as if he hadn't performed the impossible and healed her.
He treated his Serene Highness with a somewhat affected nonchalance intended to show that, as a highly trained military man, he left it to Russians to make an idol of this useless old man, but that he knew whom he was dealing with.