As a new grad, how do you deal with confrontational staff?

Ask more questions. If you are being confronted, you are doing something wrong. Bring a reference book for your are specialty snd refer to it. Stay off of your cellphone unless it it break time. Get NCC credentialing CEU and increase your knowledge. Find workshops for your skills. Take responsibility for your career. It's not all on job training. Look at your job description and work toward all functions mastery. Ask for help and clarification. "Can you show me how to? Can you observe me? Get feedback. Find a mentor

Meditate. Face a wall with your legs crossed and your hands in your lap, and learn to distinctly follow your breath. In and out. Just follow your breath. If you notice yourself having thoughts, observe them as an outside observer without any judgement, just notice them and don't attach to them, then straighten up your posture and begin to follow your breath again. Start with 5 minutes timed every morning at the same time, make it a routine in your life. Extend the amount of time each few weeks by 30 seconds if you can. 20 -40 minutes facing a wall, following your breath and noticing when you catch yourself thinking and release those thoughts and begin again to follow the Breath is the long term goal.
What this practice does is develop compassion. For yourself and for others. Its helps you recognize your own reaction to your own thoughts and to other's behaviors.
As you develop compassion for your own thoughts without judgement toward yourself, you will develop compassion for everyone you encounter.
The best way to address something you feel is confrontation is to distinctly listen to what they have to say removing your thoughts from the feelings someone else is expressing, and find the teaching about yourself and your own thoughts toward your own self from what they are saying, which leads to "Thank you for sharing that with me.", which through more of your own meditation/compassion training later on down the line will then add in "How can I help (you/this situation) ?". And your thought process becomes "I really want this person to feel better" because you realize its about them, not about you. Confrontation is someones own reaction to their own stuff. Expressing yourself kindly is easy if you make it a practice.
Is it challenging? Yep! But its a surefire way to combat any kind of your own reactivity to someone else's anger. And you get to feel better about yourself too. And you get to help SO many more people in life than just your patients and fellow staff. The world becomes a better place because you exist in it with Compassion practice.
Sidenote: as a new grad, I recommend silence and then replying, "I will do my best to do better".
Also: Read "The Four Agreements" by Don Miguel Ruiz, multiple times.
I feel I have written a pretty good answer after my 35 years of Meditation and Compassion And Nursing practice. Thanks for posing the question!

Put this quote in your toolbox: "Being wrong is erroneously associated with failure when, in fact, to be proven wrong should be celebrated as it elevates a person to a higher level of understanding."